Apr 02: Linked Structures

Learning Objectives

After today's class, you should be able to:

Explain how items are inserted into an ArrayList vs a LinkedList.
Summarize performance trade-offs for ArrayList and LinkedList.
Decide whether to use an ArrayList or a LinkedList in a program.

Lesson Outline¶

HW8-A Debrief [10 min]

Solution available in Canvas Files
Part B (60 pts) due Monday, 4/8

Act12 [45 min]

Activity 12: Linked Structures
Note: This topic is not part of HW 8

2D Arrays [20 min]

Review from CS 149 (but in Java)

Your To-Do List¶

By Friday but ideally before Thursday's class:

Do the Week 11 reading
Take Quiz09 on Canvas
Keep working on HW 8

2D Array Lesson¶

Basic usage:

Declare a 2D array variable
```
int[][] table;
```
Create a 2D array with 10 rows, 3 columns
```
table = new int[10][3];
```
Assign the value in row 1, column 2
```
table[1][2] = 159;
```
Print the array contents (not just the address)
```
System.out.println(Arrays.toString(table));
```

Nested loops (indexed):

for (int row = 0; row < table.length; row++) {
    for (int col = 0; col < table[row].length; col++) {
        System.out.print(table[row][col] + " ");
    }
    System.out.println();
}

Nested loops (enhanced):

for (int[] row : table) {
    for (int value : row) {
        System.out.print(value + " ");
    }
    System.out.println();
}

Sample Problems

int[][] data = {
    {3, 0, 7, 2},
    {0, 4, 1, 10, 5},
    {9, 0, 0}
};

Count how many zeros are in data
Get the sum of each row of data
Get the max of each column of data